Senate Republicans made their secretive health care bill public this morning, and according to many pundits, the legislation to repeal and replace Obamacare is already receiving stiff opposition from members of their own party.

Four Republican Senators – Rand Paul of Kentucky, Ted Cruz of Texas, Ron Johnson of Wisconsin and Mike Lee of Utah – released a joint statement saying they cannot support their party's health care plan in its current form

"Currently, for a variety of reasons, we are not ready to vote for this bill, but we are open to negotiation and obtaining more information before it is brought to the floor," the four said in a statement. "There are provisions in this draft that represent an improvement to our current healthcare system but it does not appear this draft as written will accomplish the most important promise that we made to Americans: to repeal Obamacare and lower their healthcare costs."

Sen. Dean Heller (R., Nev.) said he had "serious concerns" about the deep cuts to Medicaid under the Republican's bill.

"If the bill is good for Nevada, I'll vote for it and if it's not, I won't," said Heller, who faces re-election next year in a state where over 200,000 people receive health care thanks to the Medicaid expansion under Obama's law.

The Hill currently counts 12 Republican Senators whose support of the bill is either undecided or unclear. In addition to Paul, Cruz, Johnson, Lee and Heller, the list includes Susan Collins of Maine, Shelley Moore Capito of West Virginia, Lindsey Graham of South Carolina, Lisa Murkowski of Alaska, Rob Portman of Ohio and Mike Rounds of South Dakota.

Their list also includes Louisiana Sen. Bill Cassidy, a gastroenterologist who has said he wants the Republican health care plan to pass "the Jimmy Kimmel test" and not prevent children with pre-existing conditions from getting coverage. He also wants Republican's to follow through on President Trump's promises to protest preexisting condition coverage, lower premiums, and not cut Medicaid spending.

The number of Republican senators opposed to the bill is important, because Senate Majority Leader Mitch McConnell (R., Ky.) can only afford to lose support from two members if he hopes to pass the bill next week. Democrats were kept out of the process in creating the bill, and none are expected to vote in favor of repealing President Obama's signature legislative achievement.

The health care bill, Republican's latest attempt to repeal and replace the Affordable Care Act, known as Obamacare, would significantly cut Medicaid for low-income Americans and remove taxes on high-earners that helped fund subsidies to help make private coverage affordable.

According to the Associated Press, the bill would provide less-generous tax credits to help people buy insurance and let states get waivers to ignore some coverage standards that "Obamacare" requires of insurers. And it would end the tax penalties under Obama's law on people who don't buy insurance — the so-called individual mandate — and on larger companies that don't offer coverage to their employees.

"We live in the wealthiest country on earth. Surely we can do better than what the Republican health care bill promises," said Senate Minority Leader Chuck Schumer (D., N.Y.).

This is a developing story. Check back for updates.